The
word biodiversity refers to the variety of living organisms (flora and fauna). As
defined in convention on Biological diversity singed at Rio De Jenerio (Brazil)
in 1992 by 154 countries, the Biodiversity defined as “the variability among
living organisms from all sources including, inter alia, terrestrial, marine
and other aquatic eco-systems and the ecological complexes of which the area
part- this include diversity with in species, between species and of
ecosystem.” Biodiversity or Biological diversity is defined as the variability
among all living organisms from all sources, including terrestrial, marine and
other aquatic ecosystems and ecological complexes of which they are part.
‘Biological diversity’ or biodiversity is that part of
nature which includes the differences in genes among the individuals of a
species, the variety and richness of all the plant and animal species at
different scales in space, locally, in a region, in the country and the world,
and various types of ecosystems, both terrestrial and aquatic, within a defined
area.
Biological diversity deals with the degree of nature’s
variety in the biosphere. This variety can be observed at three levels i.e., genetic,
species and ecosystem.
Genetic diversity: Genetic diversity refers to the
variation at the level of individual genes. Each member of any animal or plant
species differs widely from other individuals in its genetic makeup because of
the large number of combinations possible in the genes that give every
individual specific characteristics. Tremendous amount of genetic diversity
exists within individual species. This genetic variability is responsible for
the different characters in species. Thus, for example, each human being is
very different from all others. This genetic variability is essential for a
healthy breeding population of a species. Genetic diversity is the raw material
from which new species arise through evolution. Today, the genetic diversity is
made use to breed new crop varieties, disease resistant crops.
Species diversity The number of species of plants and
animals that are present in a region constitutes its species diversity. This
diversity is seen both in natural ecosystem and in agricultural ecosystem. Some
areas are richer in species than others.
Areas that are rich in species diversity are called
‘hotspots’ of diversity and the countries with the highest species richness or
have a relatively large proportion of these hot spots of diversity are referred
to as ‘megadiversity nations’.
India is among the world’s 15 nations that
are exceptionally rich in species diversity.
The earth’s biodiversity is distributed in specific
ecological regions. There are over a thousand major eco-regions in the world.
Of these, 200 are said to be the richest, rarest and most distinctive natural
areas. These areas are referred to as the Global 200. It has been estimated
that 50,000 endemic plants which comprise 20% of global plant life, probably
occur in only 25 ‘hot spots’ in the world. These hotspots
harbour many rare and endangered species. Two criteria help in defining
hotspots namely rich endemism and the degree of threat. To qualify as hotspots
an area must contain at least 0.5 per cent or 1500 of the worlds 3,00,000
plants species as endemics
. At present conservation scientists have been able to
identify and categorise about 1.8 million species on earth. However, many new
species are being identified, especially in the flowering plants and insects.
Areas that are rich in species diversity are called ‘hotspots’ of diversity.
India is among the world’s 15 nations that are exceptionally rich in species
diversity.
ECOSYSTEM DIVERSITY:
There are a large variety of different ecosystem
on earth, each having their own complement of distinctive inter linked
species based on differences in the habitat. Ecosystem diversity can be
described for a specific geographical region or a political entity such as a
country, a state or a taluk. Distinctive ecosystems include landscapes like
forests, grasslands, deserts, mountains etc as well as aquatic
ecosystems like rivers, lakes and seas. Each region also has man- modified
areas such as farmland or grazing pastures. It refers to the variation in the
structure and functions of the ecosystem.
METHODS OF MEASURING BIODIVERSITY:
There are three perspectives measuring of diversity at
the level of community.
These are (i) Alpha diversity, (ii) beta diversity and
(iii) gamma diversity. Community diversity refers to the variations in the
biological communities in which species live.
(i) Alpha diversity indicates diversity within the
community. It refers to the diversity of organisms sharing the same community
or habitat. A combination of species richness and equitability / evenness is
used to represent diversity within a community or habitat.
(ii) Beta diversity indicates diversity between
communities. Species frequently change when habitat or community changes. There
are differences in species composition of communities along environmental
gradients, e.g, altitudinal gradient, moisture gradient, etc.
the higher heterogeneity in the habitats in a region or greater dissimilarity
between communities exhibit higher beta diversity.
(iii) Gamma diversity refers to the diversity of the
habitats over the total land scope or geographical area. The sum of alpha and
beta diversities of the ecosystems is an expression of the biodiversity of
landscape, which is considered as Gamma Diversity. Higher diversity at
community level provides stability and higher productivity. In temperate
grasslands, it has been observed that diverse communities are functionally more
productive and stable, even under environmental stresses such as prolonged dry
conditions.
BENEFITS OF
BIODIVERSITY
Utilitarian benefits
Biodiversity
contribute to our material well-being.
We obtained various productive materials from biodiversity e.g.
agricultural materials or food, fuelwood, fodder. The values of natural
products for developing pharmaceuticals, for developing and maintaining the
genetic basis of agriculture, and supporting industries based on use of species
such as fisheries and timber extraction
More than
60 wild species
have been used
to improve the world’s 13 major crops by providing
genes for pest resistance, improved yield, and enhanced nutrition (IUCN, 2012). Since agriculture began about 12,000 years ago, roughly 7,000 plant species have been used for human consumption. While most people depend mainly on domesticated species for their dietary needs, some 200 million depend on wild species for at least part of their food.
Populations in South and East Asia are dependent on complex rice-fish agro-ecosystems, where fish and other aquatic animals serve as a source of nutrition to local communities, and provide essential services for rice productivity in the flooded fields. Fisheries alone account for at least 15% of animal protein directly consumed by humans. Fisheries indirectly support additional food production by providing inputs to the aqua-culture and livestock industries.
Amphibians play a vital role in ecosystems, are indicators of environmental health, and are ‘hopping pharmacies’ being used in the search for new medicines. Yet 41% of amphibian species are threatened with extinction. In some countries, medicinal plants and animals provide most of the drugs people use, and even in technologically-advanced countries like the USA, half of the 100 most-prescribed drugs originate from wild species. According to world health Organization report nearly 80% of people live in Africa rely on traditional medicines as main source for their health care need.
More than 70,000 different plant species are used in traditional and modern medicine.
Ecosystem services
are defined as the processes and conditions of natural systems that sustain and
fulfil human life and support human
activity (Singh et al. 2006).
Biodiversity plays an
important role in the
way ecosystem function and in the services they provide.
It refers to the services provided by ecosystems like
prevention of soil erosion, prevention of floods, maintenance of soil
fertility, cycling of nutrients, fixation of nitrogen, cycling of water, their
role as carbon sinks, pollutant absorption and reduction of the threat of
global warming. We could not survive without the basic services provided by
natural systems. Many aspects of the stability, functioning and
sustainability of ecosystem depend on biodiversity.
A square kilometre of coastal ecosystem such as mangroves forests can store up to five times more carbon than the equivalent area of mature tropical forests. But these areas are being destroyed three to four times faster than forests, releasing substantial amounts of carbon dioxide into the atmosphere and the ocean, and contributing to climate change (IUCN: facts and figures on biodiversity, 2012).
Regulation of biochemical cycles e.g. Oxygen, Nitrogen, hydrological cycles etc. Biological resources are important media in biochemical cycles, without which the cycles are not complete.
Absorption and breakdown of pollutants and waste materials through decomposition, e.g., in food web
and food chains where the flow of energy goes through production consumption and decomposition without which breakdown and absorption of materials will not be complete. In an ecosystem there is no waste as decomposition will take place to purify our environment by transforming the waste to other forms of biodiversity.
Determination and regulation of the natural world climate whether local, regional or micro level through influencing temperature, precipitation and air turbulence. Biodiversity underpins ecosystem resilience and plays a critical role as part of disaster risk reduction and peace-building strategies. Forests, wetlands and mangroves play a critical role in reducing the impacts of extreme events such as droughts, floods and tsunamis. The value of the ecosystem services provided by coral reefs ranges from more than US$ 18 million per square kilometer per year for natural hazard management, up to US$ 100 million for tourism, more than US$ 5 million for genetic material and bio-prospecting and up to US$ 331,800 for fisheries (CBD, 2014).
Protective services
of biodiversity provide protection of human beings from
harmful weather
conditions by acting as wind breaks, flood barriers among others. Production of at least one third of the world’s food, including 87 of the 113 leading food crops, depends directly or indirectly on pollination carried out by insects (honey bee), bats and birds. This worldwide economic value of the pollinating service provided by insects is worth over US$ 190 billion per year for the main crops that feed the world (CBD, 2014). There have been worldwide declines in the diversity of pollinating insects that are essential for the reproduction of many plants. Wild species are important in pest regulation. Bats, toads, birds, snakes, and so on consume vast numbers of the major animal pests found on crops or in forests.
A single colony of
Mexican Free-tailed Bat eats more than
9,000 kg of insects per night, targeting especially Corn Earthworms and Fall
Armyworms, both major crop predators. Yet 18% of bat species are threatened
with extinction. A single brood
of woodpeckers can
eat 8,000-12,000 harmful
insect pupae per day, helping to maintain the
health of forests,
whilst in fruit plantations, insectivorous
birds can make
the difference between a
bumper crop or
a costly failure.
Aesthetic value
Human beings derive great enjoyment from natural environment. The shapes, structure and colour stimulate our senses and enrich our culture. This illustrate majorly in the popularity of biodiversity conservation measures and the myriad of the many organizations which fight for the protection of different organisms. A lot of money is paid to conserve wildlife for their value in nature through so many organizations. Wild species enhance our appreciation and enjoyment of the environment through: Leisure activities e.g. bird watching and nature trailing; Spotting activities e.g. spot hunting, sport fishing, diving and mushroom picking;
People from far and
wide spend a lot of time and money to visit wilderness areas where they can
enjoy aesthetic value of biodiversity and this type of tourism is known as
‘Eco-tourism’. Ecotourism is estimated to generate about 12 billion dollars of
revenue annually.
Every form of life on earth is unique and warrants respect regardless of its worth to human beings; this is the ecosystems right of an organism. Every organism has an inherent right to exist regardless of whether it is valuable to human beings or not. Humankind is part of nature and the natural world has a value for human heritage. The well being of all future generations is a social responsibility of the present generations, hence the existence of an organism warrants conservation of the organism.
Aesthetic value
Human beings derive great enjoyment from natural environment. The shapes, structure and colour stimulate our senses and enrich our culture. This illustrate majorly in the popularity of biodiversity conservation measures and the myriad of the many organizations which fight for the protection of different organisms.
A lot of money is paid to conserve wildlife for their value in nature through so many organizations. Wild species enhance our appreciation and enjoyment of the environment through: Leisure activities e.g. bird watching and nature trailing; Spotting activities e.g. spot hunting, sport fishing, diving and mushroom picking;
People from far and
wide spend a lot of time and money to visit wilderness areas where they can
enjoy aesthetic value of biodiversity and this type of tourism is known as
‘Eco-tourism’. Ecotourism is estimated to generate about 12 billion dollars of
revenue annually.
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